Five-times champion Lance Armstrong is concerned Tuesday's third stage of the Tour de France could prove treacherous.
The 210km route from Waterloo in Belgium to Wasquehal in France contains two sections on cobbled roads.
"I think everybody is worried about the cobbles - even the riders who are good on them are worried," Armstrong said.
"You could be involved in a crash and that would mean the end of your Tour. Somebody's Tour will be over on Tuesday and I could be one of those people."
The first cobbled section runs for 1.7 miles, the second, 15 miles from the finish, is 0.68 miles and also forms part of the Paris-Roubaix race, a gruelling classic known as "The Hell of the North".
Dirk Demol, assistant sporting director for Armstrong's
US Postal team, said the cobbles should not be on the route because it was "too risky".
But Armstrong said he was in two minds, although he said it would be "a shame" if some riders' races were ended on the cobbles.
He added: "At the same time, the cobbles are a big part of French cycling. If you look at Paris-Roubaix, they are a beautiful thing, if you look at it like that, you should say they should be part of the Tour."
Armstrong's former team-mate Tyler Hamilton, who broke his collarbone in a horror crash on stage one a year ago, echoed the Texan's sentiments.
Hamilton told BBC Sport: "It's not going to take a lot to knock someone off their bike on this surface. All I can do is hope that the team protects me when someone crashes.
"I can't afford another broken collarbone and neither can the team."
Despite his reservations, Hamilton said the cobblestones were "part of racing".
He said: "We have mountains, flat stages, crosswinds and cobblestones. It's all part of the fun and it's why we get on the bike every day."